Metal powder spray cutting apparatus

ABSTRACT

A metal powder spray cutting apparatus comprising a metal powder reservoir, beneath which is a chamber having a metal dropping port crossed by a gas reciprocating route, at the base of which is an expansion accumulator, while said gas reciprocating route has its one end opened in the expansion accumulator and the feeding route for a cutting jet oxygen passes through the expansion accumulator to be connected with a cutting burner, so that metal powders mixed with oxygen may be sprayed out of a spray port in the center of the nozzle at the tip of said cutting burner.

United States Patent [451 Mar. 21, 1972 Okui [54] METAL POWDER SPRAY CUTTING APPARATUS [72] Inventor: Seichi Okui, 543 Tatsurniyagara-cho,

lkuno-ku, Osaka, Japan 7 [22] Filed: May 21, I970 [21] Appl.No.: 39,316

[52] US. Cl. ..266/23 S, 239/4245 [51] Int. Cl ..B23k 5/00 [58] Field of Search ..266/23 H, 23 P, 23 Q, 23 S,

[56] References Cited UNITED STATES PATENTS 1,178,551 4/1916 Stolle et al. ..266/23 S Primary ExaminerGerald A. Dost Attorney-Christen 8L Sabol [5 '7] ABSTRACT A metal powder spray cutting apparatus comprising a metal powder reservoir, beneath which is a chamber having a metal dropping port crossed by a gas reciprocating route, at the base of which is an expansion accumulator, while said gas reciprocating route has its one end opened in the expansion accumulator and the feeding route for a cutting jet oxygen passes through the expansion accumulator to be connected with a cutting burner, so that metal powders mixed with 0x ygen may be sprayed out of a spray port in the center of the nozzle at the tip of said cutting burner.

1 Claims, 5 Drawing Figures METAL POWDER SPRAY CUTTING APPARATUS The present invention relates to a metal powder spray cutting apparatus, more particularly, a metal powder spray cutting apparatus characterized by its comprising a metal powder reservoir, beneath which is arranged a chamber having a metal powder dropping port that crosses a gas reciprocating route, at the base end of which is provided an expansion accumulator, while said gas reciprocating route has its one end opened in said expansion accumulator and the feeding route of a cutting jet oxygen passes through said expansion accumulator to be connected with a cutting burner, so that the metal powders mixed up with oxygen in the expansion accumulator may be forced to spray out of an injection port arranged in the center of the nozzle at the tip of the cutting burner. In other words, in a gas spray cutting mechanism, where a high pressure oxygen is sprayed over a part of the material which is to be cut and which is preheated by a combustible gas, the metal powders comprising pure iron powders or alminium powders are fed so as to burn those metal powders to greatly heat said part to be cut by the combustion of said metal powders, making it practicable to perform a metal spray cutting of special steel or nonferrous metal, in case of which, said metal powders supplied to the part to be cut are always uniformly sprayed out of an injection port in the central part of a cutting nozzle.

In the past, the theoretical idea of a metal powder spray cutting was patented as far back as 1910, but it is only in recent years that said idea has been put to practical use, as it became known to successfully conduct the metal powders mixed with dry air or nitrogen to a cutting nozzle, making a denial of apprehensions of accidents similar to an explosion of coal dusts in a coal mine or an explosion of flour kept in the hold of a carrying vessel, in addition todissipating all our fears of an oxidation of the metal powders due to their contact with oxygen.

However, because the structure of a nozzle does not allow the metal powders to be sprayed out of the central jet spray port of the nozzle, when conducting the metal powders by means of any gas other than oxygen, such as dry air or nitrogen, it has been necessary to supply the metal powders to the cutting jet spray port at the tip of the nozzle and from round said jet spray port. Consequently, a burning area of the metal powders at the cutting point of the tip ofa nozzle will inevitably become larger, so that a range of the metal spray in the material to be cut becomes also larger and the metal sprayed surface cannot be flat and smooth into the bargain.

But, after confirming by repeated experiments that, in case of combustion of the metal powders, no combustible gas will be produced as in case of coal dusts or flour, the applicant discovered that, even if oxygen is fed into a reservoir containing a large volume of the metal powders and sparks to be used in a metal spray are scattered within said reservoir, there is no apprehension of an explosion in the least.

The object of the present invention based upon a series of the above-mentioned experiments is to provide a metal powder jet spraying apparatus which is far more efficient than the conventional similar apparatus, because of its comprising the metal powder reservoir, beneath which is arranged a chamber having a metal dropping port crossed by a gas reciprocating route, at the base end of which is provided an expansion accumulator, while said gas reciprocating route has its end opened in the expansion accumulator and the feeding route of a cutting jet oxygen passes through the expansion accumulator to be connected with a cutting burner, so that the metal powders mixed with oxygen in the expansion accumulator may be forced to spray out of an injection port arranged in the center of the nozzle at the tip of said cutting burner.

For a more detailed description of the invention, reference will now be made to the accompanying drawings, wherein;

FIG. 1 is an illustrative view of the metal powder spray cutting apparatus, which shows a cross section of a metal powder reservoir.

FIG. 2 is an enlarged view of the metal powder reservoir alone of FIG. 1.

FIGS. 3 and 4 are illustrative views of different embodying examples of the invention having the same object as the apparatus shown in FIG. 2.

FIG. 5 is a vertical cross section of the cutting nozzle.

In FIG. 1, the gas bomb filled with a combustible gas such as acetylene and the like is shown by 1 and the valve which connects or disconnects the bomb 1 with the hose 3 is indicated by 2, while 4 represents a pressure reducing valve acting to supply to a cutting burner 5, through the intermediary of the hose 3, a high pressure combustible gas after decompressing it suitably to be used in the cutting burner 5. The bomb filled with a super high oxygen is shown by 6 and the valve connect ing or disconnecting said bomb 6 with the hose 8 is indicated by 7. A pressure reducing valve intended to supply to the cutting burner 5, through the intermediary of the hose, a super high pressure oxygen after decompressing it to be suitable for use is denoted by 9, while the metal powder reservoir arranged within a case 12 provided beneath it with locomotive wheels 11 11 is shown by 10, and the metal powder dropping port formed beneath the central part of the bottom surface 14 of said metal powder reservoir 10 is indicated by 13. The chamber fixed to the lower end of a pipe 16 formed within said metal powder dropping port 13 is shown by 15, and a gas reciprocating route formed in a direction to cross the metal powder dropping port 13 in said chamber 15 is represented by 17. The expansion accumulator made of soft rubber connected to the one end of said gas reciprocating route 17 in such manner as to close it is indicated by 18, while the expansion room formed in said chamber 15 in such condition as to open the gas reciprocation route 17 is denoted by 19. 20 is the needle valve inserted into the chamber 15 in order to adjust the orifice of a connecting route, and 21 is a desiccating container filled with a desiccant such as calcium chloride for drying oxygen which moves within a hose 8. The metal powder pressure pipe, which branches out of a hose 8 within the desiccating container 21 and which is led into the metal powder reservoir 10 in order to press down the metal powder 23 kept in said reservoir 10, is shown by 22. The pipe, which branches out of a three-way joint provided in the above-mentioned hose 8 and which connects said hose 8 with the expansion room 19 is denoted by 8A, while 8B represents a metal powder con ducting hose, and the metal powder flow rate regulation valve of a combustible gas is shown by 25. 26 is the flow rate regulation valve of a preheating oxygen, while 27 denotes the flow rate regulation valve of a cutting oxygen, and a cutting nozzle at the tip of the burner 5 is indicated by 28.

In FIG. 5, the spray port of a high pressure oxygen which is opened in the center of the nozzle 28 is shown by 29 and the spray port opened round said spray port 29 at the tip of the nozzle 28 for the mixture of a preheating combustible gas and a low pressure oxygen is denoted by 30.

In the present invention as described above, the mixture ratio between a combustible gas supplied to the burner 5 through the hose 3 from the bomb 1 and oxygen fed through the hose 8 from the bomb of oxygen 6 is regulated by the flow rate regulation valves 25 and 26, while gas is ignited by a lighter at the tip of the nozzle 28, so that the mixture of a combustible gas and oxygen will burn at the point of the spray port 30...., while oxygen flowing through the metal powder conducting hose 8B, which branches out of the three-way joint 24, will suck in the metal powder at the outlet point of the gas reciprocating route 17 on its way to the central spray port 29 of the nozzle 28 to jet together with the metal powder to perform cutting its object for cutting.

When the flow of a high pressure oxygen within the hose 8 turns toward the metal powder conducting hose SE at the three-way joint 24, and high pressure is released within the expansion room having a larger cross sectional area than that of the pipe 8A within the chamber 15, a whirlpool of oxygen will be produced within the expansion room 19 on account of a sudden release of oxygen within the expansion room 19, and

vibrations caused by said whirlpool within oxygen will be propagated into the gas reciprocating route 17. Moreover, the expansion accumulator 18 will expand and contract in accordance with the change of pressure of gas within said expansion accumulator 18. Consequently, the accumulator 18 will repeat its expansion and contraction alternately in quick succession, causing vibrations of oxygen remaining within the gas reciprocating route 17, so that the pressure of the metal powder within its reservoir 10, which converges to an orifice of the metal powder dropping port 13 from all arching points lying over said orifice, like an arched bridge spanned over it, as commonly called in Japan as an arched bridge phenomenon, and which prevents the metal powder itself from continuously falling into the gas reciprocating route 12, can be effectively eliminated and the metal powder can fall into the gas reciprocating route 17 through the metal powder dropping port 13 without interruption. In this way, the metal powder will be subject to oxygen vibrations at its dropping port 13 of the metal powder reservoir 10, and it can be freely supplied to oxygen. Moreover, when the metal powder is sucked into the expansion room 19 at the outlet of the gas reciprocating route 17, it will be uniformly mixed up with oxygen by a turbulent flow of oxygen within the expansion room 19.

In FIG. 2, a bellows type expansion accumulator 18 is shown, but it may either be a rubber balloon type as shown in FIG. 3 or a cylindrical type accumulator within which are installed a spring 18A and a piston 18B.

According to the present invention, the expansion room 19 is formed in the oxygen feeding route and a pressure oxygen coming out of a narrow feeding route flows into the expansion room 19 to suddenly expand it so as to produce oscillatory waves in oxygen within it. These oscillatory waves are effectively and advantageously utilized in the lower part of the metal powder reservoir 10, on account of which, the abovementioned so-called bridge phenomenon liable to appear in the lower part of said reservoir can be completely eliminated and the metal powder held within it can be continuously discharged downwards. As a result, oxygen and the metal powder can be evenly and uniformly mixed up and,

when applied to the material to be cut off, a stabilized heat allows the finished cutoff pieces of materials to have a smooth surface all over the cut section.

in addition, since the metal powder is mixed up with a spray cutting oxygen and then sprayed out of the spray port 29 arranged in the center of the nozzle 28, the burnt metal powder area at the cutting section of the object to be cut off is smaller than that of the conventional method wherein the metal powder mixed up with air or nitrogen is supplied to the spray port from its outside. Therefore, by such a concentric combustion, a higher heat can be effectively applied to the cutting point of said material. In addition, since oscillatory waves caused by the inherent pressure of a cutting oxygen are used in eliminating the above-mentioned so-called bridge phenomenon of the metal powder held in the lower part of its reservoir 10, it is far more economical than the conventional method wherein is consumed a kinetic energy by the use of, for instance, a vibration motor and the like.

While a preferred example of embodiment of the invention has been shown and described above in detail, many modifications thereof can be made by one skilled in the art without departing from the spirit of the invention and it is desired to protect by Letters Patent all forms of the invention falling within the scope of the following claim:

What is claimed is:

l. The metal powder spray cutting apparatus characterized by its comprising a metal powder reservoir, beneath which is arranged a chamber having metal powder dropping port that crosses a gas reciprocating route, at the base end of which is provided an expansion accumulator, while said gas reciprocating route has its one end opened in said expansion accumulator to be connected with a cutting burner, so that the metal powder mixed up with oxygen in the expansion accumulator may be sprayed out of a spray port arranged in the center of the nozzle at the tip of the cutting burner. 

1. The metal powder spray cutting apparatus characterized by its comprising a metal powder reservoir, beneath which is arranged a chamber having metal powder dropping port that crosses a gas reciprocating route, at the base end of which is provided an expansion accumulator, while said gas reciprocating route has its one end opened in said expansion accumulator to be connected with a cutting burner, so that the metal powder mixed up with oxygen in the expansion accumulator may be sprayed out of a spray port arranged in the center of the nozzle at the tip of the cutting burner. 